When hydrocarbons, such as oil, gasoline and the like, leach into surrounding land they permeate the ground into which they are spilled thereby damaging the environment. The toxic waste from such spills can prevent the owner thereof from obtaining a building permit leading to development of the land and may cause existing activities to be shut down, rendering the parcel of land unmarketable or unusable. One method of removing hydrocarbon pollutants from the ground is to encourage the growth of bacteria within the ground that feed on the toxic hydrocarbon molecules to thereby convert them into nontoxic waste products. Another method is to oxygenate the ground to thereby encourage the oxygenation of the toxic hydrocarbon molecules and convert them to nontoxic molecules.
Soil contamination arises as a result of leakage of oil and fuel tanks, the associated piping, or as a result of the process of filling and emptying such tanks. The hydrocarbons contaminate the unsaturated soil as a result of gravity and of the movement of surface water which causes contamination to spread over an area significantly greater than occupied by the tanks alone. Over time the petroleum products will leach into underlying ground spreading horizontally and vertically through the pores of the soil. Upon reaching ground water, the petroleum will pool and move with the ground water to contaminate adjacent ground.
The primary pollutants from gasoline and the like are benzene, toluene, ethylbenzene, xylene (BTEX), and methyltertiary-butyl-ether (MTBE).
In my preceding U.S. Pat. No. 6,758,959 B2 I disclosed a device for oxygenating underground water using an oxygenation unit that is lowered into a vertically drilled well the use of which is described in detail in U.S. Pat. No. 6,758,859 B2 which is incorporated herein by reference. Preferably, a plurality of such devices is employed with each device lowered into a separate well that extends below the water table. The oxygenation unit consists of a length of tubing having an upper and lower end with the tubing wall extending between them. Within the tubing is a plurality of parallel electrically conductive plates extending parallel to each other and parallel to the axis of the tubing. The plates are spaced from one another and an electric potential is applied across adjacent plates such that electrolysis will break down water between the plates into their chemical components, namely O2 and H2. Water moves across the plates by means of a pump that issues air bubbles into the neck of an inverted funnel. The bubbles of air move through the neck of the funnel and upward through the well causing upward movement of the surrounding water thereby drawing new water from the surrounding ground below the oxygenation unit.
While the device disclosed in my previous patent improves the oxygenation of the underground water, it has been found that some of the oxygen inserted into the water by virtue of the plates becomes stripped from the water by the bubbles that are emitted from the aperture of the inverted funnel. Consequently, a significant portion of the oxygen inserted into the water by the plates becomes collected in the bubbles and is released at the surface, thereby reducing the effectiveness of the device. It would be desirable, therefore, to provide and improved pump for the oxygenation unit that will reduce the amount of oxygen stripped from the water being circulated.